Steam-generator.



J. HOWDEN.

STEAM GENERATOR.

APPLICATION FILED 1011.2, 1912.

Patented Nov. 10, 1914.

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lllllllllll Illllllrllllll x a HEEEEE w E Lu. WKNW NMR INVENTOR JAMESHOWDEN BY BimQ ATTORNEY WITNE-SES J. HOWDEN.

STEAM GENERATOR.

APPLICATION FILED Ann, 1912.

1,11 6,428, Patented Nov. 10, 1914.

2 SHEBTSSEEET 2.

INVENTOR JAMES HOWDEN ATTORNEY JAMES HOWDEN, 01E GLASGOW, SCOTLAND.

STEAM-GENERATOR.

LIIGAQS.

Specification of Letters Patent.

Patented Nov. 10, 1914.

Application filed April 2, 1912. Serial No. 688,043.

To all whom it may concern:

Be it known that 1, JAMES HOWDEN, a subject of the King of the UnitedKingdom of Great Britain and Ireland, and residing at Glasgow, Scotland,have invented a certain new and useful Improvement in Steam- Generators,of which the following is a specification.

This invention relates to steam generators of the type in whichhorizontal top and bottom drums of semi-circular cross section areconnected by vertical tubes relatively small in diameter, the bottomdrums being located immediately over the fire grates, and the upperdrums being extended rearwardly to form a roof forthe combustionchamber;

' the grates being contained in a structure,

I which carries the evaporative parts of the boiler and its adjuncts buthas no other functional connection therewith.

One object of the invention is to render a boiler of this type morereadily portable, the construction adopted being such. that the boilermay, when required, be entirely completed, proved and tested under,steam and thereafter taken to pieces so that the parts may beconveniently carried by men, mules, or other available means oftransport over the most difiicultjcountry and readily put togetheragain. 1 V

. On account of its lightness, strength, du-

rability'and compactness, as also on account of its high efficiency aboiler constructed as hereinafter described is also most suitable forsmall high-speed steamships, such as torpedo boats, destroyers etc. Thetop and. bottom drums may be made so small in cross. sectionthat theycannot admit of the usual manhole doors through which the tubes can beexamined cleaned internally, renewed, or otherwise manipulated, thougheach drum has a handhole at one end for observation and partialcleaning. The drums may, however, be easily cleaned, While beingaccessible at all parts, in that each element is made in three separateparts, instead of one, as hitherto, the top and bottom drums being madeeach complete in itself, forming two parts, While the tube plates andWater tubes form a third part.

Each drum is or may be finished in one piece by suitable machinery fromone plate having diderent thicknesses, or to which small parts may beattached by rivets or otherwise. The semi-circular part of the drum overthe fire is preferably thinner than the part to Which the tube platesare attached. The thickest parts of the plates are the inturned flangesto which the tube plates are attached with their tubes; in certain casesalso parts of the drum ends are similarly thickened. These flanges areplaned all around at the sides and ends, as are also the tube plates, soas to make true faces affording a perfectly tight joint; the tube platesbeing secured to the top and bottom drums preferably by screw pins. Theend of the lower drum above the fire and the front end of the upper drumto which the uptake plates are attached are slightly curved outward, soas to bear sufiiciently Whatever pressure may be used. The front end ofeach lOWGl drum may be fiat With a hand hole flanged inward to givesuificient strength, and the back end of the upper drum may be similarlyformed with a hand hole.

When a boiler composed of a number of pairs of drums is completed, thelower drums are united by equalizing Water pipes at the front ends ofthe same, While the upper drums are united by an equalizing steam pipe,as many pairs of drums being used in a ,single boiler as is necessaryfor the amount of steam required for one unit. A very small boiler mayconsist of only one top and bottom drum with the connecting tubes andtube plates, the drums and grate beingmade sufficient in length to givethe amount of steam required. In all ordinary cases, however, whenconsiderable power is required, one grate may be made sufficiently wideto serve two or even more pairs of drums.

- The complete cleaning of the drums and tubes or renewal of tubes maybe easily accomplished by the detachment of each element from the othersand removal of one or more as may be required, so that the tubes andtube plates may be separated from the.

drums. Such operations can be accomplished in a short time, and the tubeplates and drums again put together and restored in their respectivepositions in the boiler framing. In boiler units with a considerablenumber of drums one or more may be removed and the rest of the boilerstill used, blind flanges being provided on the short branch pipes orbranches connecting them to the steam equalizing pipe. The equalizingwater pipes on the front end of the lower drums are treated in similarmanner when any of the drums are removed. In cases where extremelightness is not of special importance, the front end of the lower drumand the back end of the upper drum, both having hand holes, may beriveted as separate pieces into the drums, these ends not being exposedin any way to the fire gases.

From one end of the steam collecting pipe the saturated steam is leddown by a pipe to a horizontal cross branch or box a part of which isflattened to form a tube plate into which superheating tubes are fixed.These tubes after entering the combustion chamber are bent upward andafter passing across the combustion chamber horizontally near to theupper drums pass through into a similar cross branch or box on the otherside of the boiler at a higher level than the first cross branch or box,doors being provided to afford a means of access. From the second branchor box the superheated steam is led up to the main steam pipe, so as tobe used as superheated steam. Stop valves are provided so that thedegree of superheat can be regulated according to the extent of openingof these valves. If desired, means may be provided for flooding thesuperheater tubes.

In the accompanying drawings Figure 1 is a part front elevation, artvertical section; Fig. 2 is a longitudinal vertical section at rightangles to Fig. 1 and Fig. 3 is a part horizontal section of a boilerembodying the invention, said boiler, including two furnaces each fittedwith two elements. Figs. 4 and 5 are vertical sections at right anglesto each other of a portion of a lower drum. Fig. 6 is a developed planview showing one form of plate suitable for the construction of a drumin one piece, the thickened portions being indicated by hatched lines.Fig. 7 is a horizontal section showing the staggered arrangement of theends of the feed water heater tubes. Figs. 8 to 12 show modifiedarrangements of the feed water heater tubes and boxes. Fig. 13 shows amodified construction of the superheater boxes.

Referring to the drawings, the boiler comprises upper drums A and lowerdrums B, said upper drums being connected by means of short branches Oto an equalizing steam pipe D. Water tubes E are connected to top andbottom tube plates F and G, as shown particularly in Figs. 1 and 2, saidtube plates being secured to the upper and lower drums A and Bpreferably by screw pins,

the jointing faces on both drums and tube plates being made suitable forthis purpose.

As shown articularly in Figs. 4 and 5,- the inturned anges on the drumsare thickened for'attachment to the tube plates, the drums being made inone piece from a single plate of substantially the shape shown in Fig.6, the'thickened portions of the plate .b'eing indicated by hatchedlines. I

The space between the inner elements is wider than the space between theinner and outer elements, on account of the brickwork separating the twofurnaces. It is preferred to provide a partition H, Fig. 3, between theelements in each furnace, so as to prevent passage of the gases from onefurnace to the other when one furnace is not being utilized.

Each upper drum may be formed with a thickened extension located overthe combustion chamber I, as indicated in Figs. 8, 10 and 11, beingfaced up level with the sides and front end of the drum to which theupper tube plate is jointed, the upper tube plate being substantiallythe same length as the tube plate on the lower drum, and the saidextensions being stiffened to bear the working pressure by means of theusual bridges and stays as shown.

The saturated steam is led from one end of the collecting pipe to aheader-J which is flattened at one side to receive the supsrheatingtubes K which pass through a door L at one side of the combustionchamber and, after being bent upwardly, as shown, pass beneath thebottom plates of the upper drums A,-thence through a door M on theopposite side of. the combustion chamber to a header N. Alternatively,the headers J and N may be of the construction shown in Fig. 13.

A stop valve 0 is fitted by preference on the header N and connected tothe main steam supply pipe, and a valve P is connected to the collectingpipe and to the main steam supply pipe. This valve P is of sufficientsize to supply all or nearly all the steam evaporated by the boiler, andis used in conjunction with the valveO for'the purpose of giving asupply of steam more or less superheated.

As shown in Fig. 1, the lower drums B are supported at their front endswhere they are protected'from the action of the hot gases, and withinthe said lower drums at the front ends thereof are diaphragm plates Qwhich cause the front tubes E to act as downcomers and also insurecollection of sediment. Connecting the bottom drums B at the front endsis a common feed water pipe R which may also be used as a commonblow-off.

At the rear of each combustion chamber are or may be arranged lower, orlower and upper, water boxes disposed horizontally and of triangular orother suitable form in cross section. A lower water box is shown inFigs. 8 and 9, and upper Water boxes are shown in Figs. 10, 11 and 12.The boxes S may be made each in one piece but with separate doors T foraccess to the interior or may comprise sections suitably connectedtogether. Fitted to said boxesare tubes U preferably of less diameterthan the upright water tubes E of tha'generator.

The said tubes U are staggered, as shown in Fig. 7, and are so placedthat the touch, or

nearly touch, each other vertically and thus form a water wall at therear of each combustion chamber. The upper water boxes are situated nearthe lower side of the said upper drums where they extend rearwardly overthe combustion chamber. The lower boxes are preferably placed above thelevel of the fire grate and are protected more or less from the heat bymeans of brickwork or other non-combustible material. Feed water is ledto the lower box or boxes by means of a pipe V provided with a nonreturncheck valve, and flows through the tubes U, by way of the upper box orboxes, if these are provided, into the upper drums, the feed'water beingheated in its passage by the action of the hot gases on the tubes U.

Having now described my invention what ll claim and desire to secure byLetters Patent of the United States is 1 In a water tube steamgenerator, in combination a top and a bottom drum, each drum being ofsemi-cylindrical formation and having its ends integral with the body,the edges of the body and of the ends being inturned and of thickersection than the rest of the drum, said edges forming the boundaries ofan aperture, and a fiat tube plate fitted to said inturned edges andclosmg said aperture, and water tubes connecting the tube plates of thetop and bottom drums.

2. In a water tubesteam boiler, in combination, a top and a bottom drum,each drum comprising a semi-cylindrical body having its ends integralwith the body; said ends and body belng inturned and thickened at theedges; said edges affording the boundaries of an aperture; flat tubeplates removably fitted to the inturned edges and closing saidapertures; the tube plates for the-top and bottom drums being of equallength; and Water tubes connecting the tube plates.

In testimony whereof I have signed my name to this specification in thepresenceof two subscribing witnesses.

JAMES HOWDEN,

Witnesses 'WALLAQE FAIRWEATHER,

JOHN MCCLEARY.

